jeudi 11 octobre 2007

Rigid Rotation Criteria

Rigid rotation criteria were wrong. The quantity I2/I1 is meaningless, as I's are not absolute values.

Interesting phenomena that I realized today --- in run 1201 - 1300, I2 is not varying, even though e2 is oscillating (though the amplitudes are sometimes suppressed, other times just as much as predicted from the Kozai).

Thus, the Kozai oscillation is in play, even though the inclination is NOT varying!!!!

I have to review the Kozai again --- probably from Fabrycky & Tremaine. What happens first? As far as I understand, the key is the conservation of Jz -- z-component of the angular momentum. That results in the oscillation of the orbital plane (= change in I). To conserve the total angular momentum, e oscillates accordingly.
The oscillation is happening for the outer planet, without varying I. That means J2 is being lost to somewhere. To where?

It's not a numerical error. According to info.out files, angular momenta are conserved to the order of -10 or even smaller. Angular momenta in the system are NOT lost.

Actually, I have to check this more carefully. In some cases, I2 does vary. Also when the initial I2 is close to 40 or 140, the effect may be too small in the plots.

In many cases also, the Kozai oscillation ensues but with suppressed amplitudes. Why does this happen? I may have to go back to the derivation of emax from the Kozai.


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